Overview

• The JMA raised the eruption alert from Level 1 to Level 2 at 5 a.m. on August 4, marking the first escalation since March 2021.
• Seismologists recorded about 40 volcanic earthquakes beneath the Yūgama crater from the afternoon of August 3 to the morning of August 4.
• Authorities closed an 8.5 kilometer stretch of National Route 292 between Sesshogawara parking area and Manza junction following the unrest.
• Monitoring data revealed gradual shallow ground uplift around the crater since June 2024, indicating deepening volcanic activity.
• Kusatsu Town’s mayor emphasized that the hot-spring district lies over five kilometers from Yūgama and remains unaffected.